长庆油田污水配聚溶液黏度降低的原因分析

Analysis of factors to viscosity reducing of polymer flooding in Changqing oilfield

聚合物驱是提高原油采收率的重要措施之一,长庆油田采用清水配制聚合物母液,再用联合站处理后的污水进行稀释的方法配制聚驱溶液,但其黏度在未达到储油层已降低至15 m Pa·s以下,严重影响驱油效率。本研究首先对联合站内各工艺段污水进行水质分析,然后通过室内配制模拟污水及聚合物溶液,考察了K+、Na+、Ca2+、Mg2+、Fe2+、溶解氧及水处理剂对聚合物溶液黏度的影响。结果发现,Fe2+是导致聚合物黏度降低的最关键因素。此外,高价金属离子、溶解氧和水处理药剂对聚合物溶液黏度也有较大影响。

Inpouring polymer flooding is one important process to enhance oil recovery. Polymer solution is prepared with fresh water and diluted with waste water treated by joint station in Changqing oilfield.The viscosity of the polymer flooding drops rapidly, which is lower than 15 m Pa·s.This research starts on analysis of waster water quality. The factors such as K~＋,Na~＋,Ca^（2＋）,Mg^（2＋）,Fe^（2＋）,dissolved oxygen（DO）and oil and water treatment chemicals,which effect the viscosity of polymer solution,are investigated by using indoor simulation experiment.The results show that the content of Fe^（2＋） is the main factor to the viscosity of polymer solution.Besides,ion with high valence,DO oil and water treatment chemicals have a significant effect on the viscosity of polymer solution,too.